Core D provides support to all individual projects in the program and provides methodology for the measurement of phospholipids, acylcarnitines and malonyl-CoA; isolation of mitochondria and enzyme activity measurements; preparation of tissue specimens and isolated mitochondria for morphological analysis. The specific aims are: 1. Isolation of heart subsarcolemmal and interfibrillar mitochondria from control and microembolizationinduced heart failure dogs for oxidative phosphorylation measurement by Project 4. 2. Determine the activity of the electron transport chain enzymes. 3. Provide silica gel column chromatographic class separation of lipids and high performance liquid chromatographic analysis of phospholipid classes. 4. Provide quantitative and qualitative analysis of acylcarnitines, malonyl-CoA and phospholipids using high performance liquid chromatography/electrospray mass spectrometry. 5. Provide molecular weight and amino acid sequence determinations of modified proteins and/or peptides using high performance liquid chromatography/electrospray ionization mass spectrometry. 6. Provide additional analytical support procedures that the Core has the resources and expertise in even though the procedures are of limited scope in a particular project.